Improvement in insulators for telegraphs



S. F. VAN CHOATE. Telegraph-WW6 lnsulatorr Patented Aprii 4, 1865.

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UNITED STATES PATENT OFFICE.

S. F. VAN OHOATE, OF NEW YORK, N. Y.

Specification forming part of Letters Patent No. 47,141 dated April 4,1865.

To all whom it may concern:

Be it known that I, S. F. VAN GHOATE, of the city and State of New York,have invented an Insulator for Telegraphic Purposes; and I do herebydeclare that the following, taken in connection with the drawings whichaccompany and form partof this specification, is a description of myinvention sufficient to enable those skilled in the art to practice it.

The great difficulty experienced in transmittin g and receivingtelegraphic signals through or by means of long stretches of wire orother conductors in rainy weather or in humid atmospheres arises, notfrom the fact that the electric fluid passes from the wire-conductorthrough the substance of the insulator-glass or bone rubber, but it isthe fact that the electric current or fluid finds a path to the groundalong the surface moisture or film of vapor or other conducting-matterwhich has condensed or settled upon the outer surfaces of the wire,glass, or bone rubber and the surfaces of the post or other suspendingapparatus. This film may not be perceptible to the eye or to the touch,yet it may be sufficient to carry off a portion of the current. Theseescapes, as in the case of posts, form so many leaks of the current tothe ground, and consequently returns of the same to the opposite pole ofthe battery, (this being the normal tendency of the electric fluid,) sothat the supplying battery-force fails to reach the distant instrumentwith full vigor, or, in other words, fails to complete its circuitthrough the distant instrument, but turns back at these variousescaping-points, forming the difficulty which telegraphers call a groundor return, whereby the distant effect desired to be produced upon thereceiving apparatus does not take place. Many devices have beenpresented with a view to obviate this serious difficulty, and whichheretofore has rendered telegraphing so uncertain during rainy or foggyweather. The following is my plan for obviating this difficulty, whichis called Van Ohoates Insulator.

In the accompanying drawings, Figure 1 is a perspective view ofmyinsulator in the shape of a wooden pin-bracket, showing the under sideand the cavity A formed in it. This wooden pin is turned out in a commonlathe, and is nicely rounding on top, in order to turn the rain ofi'.

The peculiar-shaped cavity, with its angles or grooves, as shown at b bin Figs. 1 and 2, forms the principal feature of this invention. Thehub-shaped barrel or cylinder 0 c, Fig. 2, of the cavity-plate isveryimportant. It serves for two purposes. It closes up the large cavityA, so as to prevent the moisture from set tlin g or condensing in thechamber, while the lower projection or lip, (Z (1, forms a drip toprevent the rain from running into the cavityspace. The drawing is madeupside down. When the insulator is secured to the post or other supportthe hook hangs underneath, so as to hold the wire. The cavity-plate isbeveled on its outer under edge, and fits tightly in the groove cut intothe wood, and is secured in its place by means of two small brads ornails, as at c c.

The object of the peculiar-shaped cavity A and the plate D is that whenthe whole are combined a dry space is secured between the hook and theouter surfaces of the wooden pin. This dry space prevents the electriccurrent from escaping from the wire to the ground by means of anydampness which might be settled or formed upon the outer surfaces of thewire, hook, bracket, or post. The open space around the stem or neck ofthe hook at ff,

Fig. 2, is so small, and by means of the cylinder shape of the hub ofthe plate D the moisture would have to follow up this small space aconsiderable distance before it could spread on the roof of the cavityaround the base of the hook.

The object of the second groove, 1) b, or indentation at the angle ofthe cavity is to give corners and jambs at various angles to prevent thedampness or moisture from spreading should it get inside of the cavity,while the lower projection of the cylinder of the plate forms a drip toprevent the rain or other water from running into or closing up theopen= ing around the neck of the suspending-hook.

Fig. 5 shows a plate with an outer rim or drip, as at g g, which is adouble protection against the rain. running into the hollow around thehook.

In order to protect the surfaces of the woo den bracket, as well as theplate and hook, and to prevent the surfaces of the metal from oxidatingor absorbing moisture, and also in order to keep insects out of thecavity, particularly to prevent spiders from building their webs insidethe cavity or on the bracket or hook, I

coat them over, inside and out, with a composition whose principal baseis asphaltum, and whose principal solvent is naphtha. This compositionforms a black varnish or paint, which makes the surfaces of the wood andiron impervious to moisture and protects the former from oxidation,while it renders the latter imperishable in the air.

What I claim is- 1. The combination of the cavity A, face-

